Artillery Ambush in DnD 5e
Inspired by "When Trumpets Fade"
Fire Upon a Quiet Day
The following encounters put your players characters on the wrong end of a deadly rain of fire. If they are to survive they need to be quick, quiet, and a little clever. This is intended for four level 5 player characters, but can easily be altered to suit your table. The situation breaks down into three parts:
- Encounter 1: Artillery barrage on party run as a trap
- Encounter 1.5: Sneak towards enemy position run as a skill challenge. Possible repetition of Encounter 1.
- Encounter 2: Attack on the enemy artillery position run as a combat
Encounter 1: Rain of Fire
This first encounter occurs as the party walks through a forest. Why they are there and for what purpose is up to you, but that will matter little once they come under fire. The only thing that will matter is survival. For they will be under attack from large canisters of alchemist's fire launched from a far off enemy. This trap is based off of the Dungeon Master's Guide page 121 tables for trap save and damage severity.
Alchemist's Fire Barrage Trap
Trigger: Party gets within roughly 1000 feet of enemy position. Party should roll initiavtive.
Timer: Barrage will occur on initiative count 20 of each round for 2-3 rounds. The entire party should be surprised by the barrage round one, unless they have a feat or other means to avoid being surprised by enemies.
Harm: Two canisters of fire land each turn. All creatures in the explosive area must make a DC 13 Dexterity saving throw, taking 3d10 fire damage on a failed save and becoming engulfed in flame. While engulfed in flame, a creature takes 1d10 fire damage at the start of their turn. The flames can be extinguished if a creature within 5 feet of the engulfed creature uses their action to douse the flames.
To select which party members will be targeted by each barrage, number your player characters starting from 1, and roll a die that accommodates all player character's numbers. If the result is a player character's number, that character is targeted. A character cannot be targeted by more than one barrage a round.
For example, a party of four characters will be numbered 1,2,3,4 and thus can be accommodated on a d4. The d4 is rolled and is a 3. Thus player character 3 is targeted and must make the save. A group of five characters would require a d6, and the roll of 6 can either mean no one is targeted by the barrage, or one character of your choice is targeted.
Confined Space: Any party member that moves 60 feet in one direction can no longer be targeted by the barrage. Cover can be used to increase chase to succeed save.
Encounter 1.5: Hunting and Hunted
This encounter occurs as the party tries to make its way towards where they assume the enemy is while trying to avoid the enemy figuring out where they are and firing again. This is a skill challenge, as taken and edited from 4e Dungeons and Dragons.
Basics of a Skill Challenge:
- Acts as an abstraction to shorten the amount of time to show numerous steps and actions to reach a goal.
- String of skill checks where successes and failures are tracked. Successes lead group closer to their goal, while failures lead to new danger.
- Each check is made by a party member proficient in an applicable skill and each skill can only be used once per challenge.
- Checks can be called for in a particular skill, or the players may think of how to best use their character's abilities to assist the group in the current situation.
More information about skill challenges can be found in this video by Matt Colville: Skill Challenges!
Skill Challenge to Find the Enemy
- DC for checks made is 13.
- Four successful checks, will result in success. Group reaches enemy position and the enemy is surprised if the group attacks.
- Three failed checks, will result in failure. Group comes under fire again by enemy similar to Encounter 1. This time the barrage comes from much closer and the group can make their way towards the firing position, with the enemy prepared for their arrival.
- Most applicable skills
- Athletics: Scamper up rough terrain, run through brush without losing speed or falling, move quicker than the enemy would anticipate.
- Perception: Hear far off voices of the enemy and follow them.
- Sneak: Slink through the forest without making noises the enemy can hear.
- Survival: Look for tracks of large creatures in forest to follow to enemy, ensure party does not get turned around and head the wrong direction.
Encounter 2: Fire First, Questions Later
The final encounter against the fire barrage occurs when the party engages the enemy at close range. Depending on if the party succeeded on the skill challenge, the first round of this combat can be devastating for the enemy. This encounter is where the enemy is finally revealed to the party. Your campaign may require a different enemy, but I lay out a hobgoblin war band as an example. All the enemies used come from the Monster Manual, specifically page 186 for the hobgoblins and page 237 for the ogre.
Staring Down the Barrel
Enemy: The hobgoblin war unit is split into two groups, the fire hucker ogre (Ogre, MM 237) and its two assistant hobgoblins (Hobgoblin, MM 186), and the hobgoblin captain (Hobgoblin Captain, MM 186), with six hobgoblin soldiers (Hobgoblin, MM 186). The fire hucker and its assistants spend all their actions combined to start up fire barrages similar to those dealt with in Encounter 1. If your group is struggling to survive the attacks, perhaps reduce the effectiveness of the hucker at this closer range by giving them advantage on their saves or the hucker can only fire a single canister of alchemist fire a round.
The hobgoblin captain and their soldiers will all attack from range with bows initially, switching to their swords as party members get with 30 feet.
A retreat will be called by the captain if half of their forces, including the hucker and assistants, are killed in the combat.
Danger: This is a deadly combat for four level 5 characters. A surprise round may help, but the party will have difficulty surviving without taking out the hucker. There is an intrinsic way to accomplish this; explode the alchemist fire canisters the hucker is using as ammunition.
Canisters: If the alchemist fire canisters take fire, force, lightning, radiant, or thunder damage, an effect identical to the fireball spell will erupt form them, with the center of the effect at a location of your choosing within 5 feet of where the canisters took damage. These canisters should be placed such that the hucker and its two assistants are always within the blast radius if they explode. No matter the damage dealt by this blast, the hucker should be killed by it. This can be due to additional canisters on it adding damage or it already being weakened from the combat.
If you want to reduce the likelihood these canisters will be attacked round 1, though a mobile character with a cunning player may still do so, ensure that at the start of combat they are out of line of sight of the player character group. Hobgoblin soldiers obscuring vision, some dense foliage, or even the hucker team themselves blocking the pile can ensure the player characters must reposition before the target becomes available.
The Aftermath
Once the alchemist’s fire canisters explode and kill at least the hucker and its two assistants, if not more hobgoblins, the party should be very likely to outmatch the rest of the forces against them. If they are still outmatched, perhaps they will be taken prisoner and will get to see the rest of the hobgoblin army that is soon to march through these forests.
So...Can We Loot Them?
No doubt upon finishing combat, your party will want to loot whatever they can from their fallen foes. A few canisters of alchemist fire may still be usable, which can either:
- Have the properties of an alchemist’s fire (flask) from the Player’s Handbook page 148-151, but with several uses if poured (safely!) into smaller containers
- Do 3d10 fire damage + 1d10 fire damage per turn on a failed save, but requires an 18 STR to throw, and targets have advantage on the save if beyond 20 feet from the thrower. Maximum throwing range of 60 feet.
In addition, there is whatever hobgoblin armor and weapons weren't charred by the blast. Gold and other such goods will be of limited supply due to this being a group of soldiers, which don’t keep a lot of money on them. A few gold can be around as you see fit.
During the looting is a great place for you to put a hook for the next adventure or location you want the party to explore. Maybe the hobgoblin captain has a letter that details the upcoming attack on a nearby town. Or the hobgoblins were tasked with guarding the area because they have found a dungeon nearby. Whatever the reason for this attack, it should tie into your campaign and what is happening in it.
If you need a place to go from here, because you are out of ideas, like many of us are from time to time, Red Hand of Doom is great inspiration for a campaign with hobgoblin enemies! The book is from 3e Dungeons and Dragons, so if you want a full conversion check Here for a good breakdown.
Enjoy!
From the Green DM
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